Drill grinding device



9, 1943. N HOERST 2,313,641

'I DRILL GRINDING DEVICE l Filed April 9, 1941 2 sheets-sheet 1 VNHmQrsQMarch 9, 1943. v. N. HoERs-r DRILL -GRINDING DEVICE Filed April 9;,1941.2 Sheets-Sheet 2 MN R, mv Po uw xv.

um.. icFccccrEEcr-scc AW www VNHaers Patented Mar. 9, 1943 UNITED STATESPATENT OFFICE 2 Claims.

This invention relates to a means for grinding or sharpening twistdrills.

An object of this invention is to provide an improved holder for a twistdrill by means of which the drill can be accurately ground and thedesired clearance of the cutting edge formed.

Another object of this invention is to provide a drill grindingapparatus which includes a vertically adjustable support and ahorizontally movable carriage on the support, the carriage beingprovided with means for not only clamping a drill thereto but also withmeans whereby the drill may be rocked relative to the grinding wheel,the latter means including means whereby the rockable portion of thecarriage may be very finely adjusted to obtain the desired uniformsharpening of the drill lips.

A further object of this invention is to provide a grinding structurewherein the drill can be engaged with the periphery of the grindingwheel instead of the side face of the wheel.

A further object of this invention is to provide a structure of thiskind which can readily be adapted to either right or left hand drills.

To the foregoing objects and to others which may hereinafter appear, theinvention consists of the novel construction, combination andarrangement of parts as will be more specifically referred to andillustrated in the accompanying drawings wherein are shown embodimentsof the invention, but it is to be understood that changes, variationsand modifications may be resorted to which fall within the scope of theinvention as claimed.

In the drawings:

Figure 1 is a top plan partly broken away of a drill grinding machine orapparatus constructed according to an embodiment of this invention.

Figure 2 is a detail side elevation partly broken away of the device.

Figure 3 is a sectional View taken on the line 3-3 of Figure 1.

Figure 4 is a sectional view taken on the line 4-4 of Figure 1.

Figure 5 is a fragmentary side elevation of the eccentric adjustingwheel or knob.

Figure 6 is a fragmentary sectional view taken on the line 6-6 of Figure3.

Referring to the drawings, the numeral I designates generally anabrading wheel which is adapted to be mounted on a rotary shaft (notshown) and operated from a suitable power means. A combined basesupporting plate and collector I I is provided with a liquid holding panor reservoir I2 within which the wheel I0 is adapted to rotate. The basemember II extends laterally of the opposite faces of the wheel I0 andalso extends forwardly as at I3 of the wheel I0.

The marginal edges lof the base member II are provided with upstandingside flanges I4 and opposite end flanges I5 so that the ground materialwill be retained on the upper surface of the combined collector andsupporting member II. The supporting member II is adapted to have asuitable standard or the like (not shown) whereby the base plate I I maybe supported in operative relation with respect to the wheel I0.

The base member II is provided on opposite sides of the wheel I0 andslightly forwardly thereof with a pair of sockets or sleeve members I6and Il. These socket members I6 and I1 are of like construction and eachsocket member is formed with an upwardly projecting cylindricalextension I8 which extends upwardly above the upper surface of the baseplate II as shown in Figures 3 and 4.

A carriage supporting plate I9 is disposed above the upper surface ofthe base plate I I and has secured thereto a cylindrical solid stem orshank 20 which slidably engages in the extension I8 and in the socketI6. The lower end of the stem or shank 20 has a concave recess 2|therein in which the upper end of a shank adjusting screw 22 is adaptedto engage. The screw 22 is threaded through the bottom wall 23 of thesocket I6 and is provided with a knurled knob or operating member 24disposed below the bottom wall 23.

The carriage supporting plate I9 is formed in the upper surface thereofwith a longitudinally extending horizontal keyway 25 in which a key 26carried by a movable carriage 2l is adapted to slidably engage. Thekeyway 25 and the key 26 are formed in dovetail fashion and preferably agib or liner 28 is interposed between one inclined edge of the key 26and the adjacent face of the keyway 25 as shown in Figure 4. Thecarriage supporting member I9 is provided at one end thereof with anupstanding lug or ear 29 through which a carriage adjusting shaft 3U isjournalled.

The shaft 30 is provided with an annular .groove 3|, adjacent theforward end thereof, in

which a shaft locking pin 32 loosely engages so that the shaft 30 willbe held against endwise movement relative to a lug or ear 35 but will bepermitted free rotary movement. The outer end of the shaft 30 is formedwith a handle 33 and the shaft 3U is also formed with threads 34 whichthreadably engage the lug member 29 integral with the plate I9. Theshaft 30 may be locked in adjusted position by a lock nut 34a whichbears against the lug 29.

The carriage 21 has formed integral therewith a pair of upstandingparallel ears or bearing members 36 and 31 which extend upwardly fromthe upper surface thereof in substantially the longitudinal center ofthe carriage 21 and the inner faces of the bearing members 36 and 31 areoppositely tapered as at 388L and 31 respectively. A spindle 38 isdisposed in horizontal position and is rotatably mounted throughopenings 39 and 48, which are formed in the ears 36 and 31,respectively. The spindle 38 is provided with threads 4I at one endthereof and at the opposite end is formed with a knob 42. A washer 43 isdisposed about the spindle 38 andis interposed between the outer face ofthe ear 36 and a spindle locking nut 44 which is threaded onto thethreads 4I of the spindle 38.

A second washer 45 is mounted on the spindle 38 and is interposedbetween the knob 42 `and the outer face of the .ear 31. A substantiallyfrustoconical body or eccentric 46 is fixed as by a pin 41 on thespindle 38 between the ears 36 and 31. The eccentric 46 is provided atits smaller end with a frusto-conical bearing surface 48 and is alsoprovided with a frusto-conical bearing surface 49 at its larger or baseend. The frustoconical bearing surfaces 48 and 48 are of slightlygreater diameter than the outer surface of the frusto-conical body 45.The eccentric member 46 is annular in transverse section and the axialcenter of the spindle 38 is disposed at one side of the axial center ofthe body 46. A V-shaped drill holder, or cradle 56 is disposed above thecarriage 21 and has formed integral therewith a pair of downwardlyextending ears and 52. Theshaft 38 is locked against rotation by a setscrew 38a which is threaded through the ear 36.

The ear 5I is provided with a tapered or frusto-conical opening 53, inwhich the frustoconical bearing member 48 engages and the ear 52 isprovided with a tapered or frusto-conical opening 54 in which thefrusto-conical bearing surface 49 engages. The holder 50 is rotatable orswingable on the bearing members 48 and '49 so that a drill D which ispositioned in the V-shaped holder 5i) may be rocked relative vto theperipheral surface of the abrading member I0. The bearing members 38 and31 are provided'on their inner faces with tapered or oppositely inclinedfaces 36a and 31=1respectively, so that the ears 5I and 52 may moverelative to the shaft 38 when the cradle 58 is rocked on the eccentric46. The holder 58, on its opposite longitudinal edges, is provided witha pair of horizontally disposed and outwardly extending anges 55 withwhich a pair of drill clamp holding members, generally designated as 56and 56a are adapted to engage. The holding members 56 and56a are ofidentical construction and each comprises a truncated V-shaped clampingbody 51 which is formed at its divergent ends with vertical extensions58 terminating in inwardly projecting lugs 59 which are engageablebeneath the flanges 55, as shown in Figure 4. Set screws 58a engagethrough the extensions 58 for locking the holding 'or supporting membersin adjusted position.

The truncated top 68 of each clamping member 56 and 56a`is provided witha nut member 6i and threaded shafts 62 and '62a threadably engagethrough the nut members 6l and are provided at their upper ends withoperating 'members 63 and 63a. The lower end of the shaft 62 Ahasflxedly mounted thereon a drill clamping jaw 64 which is disposed invertical alignment with the apex of the V formed by the holder 50 sothat when the jaw 64 is lowered to a clamping position, the drill D willbe tightly held in the holder 58 with the axial center thereof invertical alignment with the axial center of the shaft 62 and in thevertical plane of the apex of the V formed by the holder 50.

The shaft 62a has swivelly mounted thereon a swivelled head or floatingcenter 64EL having a drill center engaging pin 64b. If desired the head64a may be turned about 90 degrees so that the head 64EL will abut theVend of the drill D without engaging in the center of the drill.

The holder 50 on the inner surface thereof and on one side has a drillpositioning member 65 mounted thereon which is of substantially V-shapein transverse section and which is adapted to engage in the groove of atwist drill.

A plate 66 is formed with the drill positioning member 65 and isprovided with an elongated slot 61 in which a fastening member 88engages. The fastening member 68 is constructed in the form of a machinescrew which is threaded into the adjacent side of the `holder 50 so thatthe drill positioning member 65 may -be shifted inwardly or outwardlywith respect to one side of the holder 56. When the clamping members 55are in clamping position, they will be disposed as shown in Figures l, 2and 3 adjacent the opposite ends of the holder 58 so as to tightly clampthe drill D in the holder 58 with at least one end of the drill Dprojecting 'forwardly of the holder 50 for Contact with the periphery ofthe abrading member I0.

rIhe two ears 5I and 52 are arranged so that when the holder 58 isrocked on th'e eccentric bearing members 48 and 49, the ears 5| and 52may7 'move so as to thereby move the holder 50. This movement willprovide aslight clearance on the cutting end of the drill back of thecutting edge thereof, the amount of the clearance depending on therelative position of the eccentric body 46 as determined bycircumferential'adjustment of this body 46 through the adjustment of thespindle 83 and the knob 42. The outer face of the knob 42 is providedwith a plurality of circumferentially arranged graduations 69 and theear 31. at the upper portion thereof is provided with a stationarypointer l16 by means of which the user of this device will be able todetermine the relative position of the eccentric 46.

The two sockets I6 and I1 are disposed 'with the axial centers thereofon an angle of 'thirty degrees with respect to the cylindricalperipheral surface of the abradingmember I8 so as to thereby grind theforward Vend of the drill D on the desired angle. The ear 52 maybe'provided with an outwardly projecting stop member 1| which, in oneposition of the ear 52, is adapted to engage the ear 31 so as to therebylimit the rocking movement of the holder 58 in one direction. This limitof the rocking movement of the holder 58 may be at the point Where theforward end of the drill D swings out of contact l'with the peripheralsurface of the abrading wheel I8.

In order to provide a means whereby therholder 58 with the carriage `21may be disposedat the desired angle with respect to the peripheralsurface of the abrading wheel I8, the socketsI and l1 may be providedwith set screws 12 which engage the shank 28. In this manner the shank28 is held against rotary movement with respect to the socket member I6andthe tightening "of the set screw 12 will ilrmly hold the shank orstem 2U in the adjusted position within either of the sockets I6 or l1.The two sockets I6 and I1 are provided so that both right and left handdrills D may be ground or sharpened, the socket I1 being used for lefthand drills.

In the use and operation of this structure the drill is tightly clampedin the holder 50 by the clamping member 62 and the positioning member62@- and is positioned by adjustment of the positioning member 65 sothat one lip of the drill will be disposed in a position for contactwith the peripheral surface of the abrading member lil. The height ofthe carriage holder i9 and the carriage 21 is adjusted by means of thecarriage adjusting screw 22 and when this position has been obtainedwith the axial center of the drill D about ten or fteen degrees belowthe axial center of the abrading member Ii), the locking screw 12 istightened. Adjustment of the spindle 38, by means of the knob 42, willregulate or control the amount of movement of the holder 5i) as it isrocked relative to the abrading member l!) through the grinding zone soas to thereby form the desired clearance back of the cutting edge of thedrill lip. The holder 56 may be adjusted toward or away from theabrading member l0, by turning the threaded shaft 30 which will move thecarriage 21 toward or away from the abrading wheel l0. When the drill isdisposed in the desired position for contact with the periphery of theabrading wheel lo, the 'shaft 3Q may be locked by the lock nut 34a so asto prevent accidental shifting of this carriage. In this manner one lipof the drill D may be sharpened to the desired degree and after this onelip has been sharpened, the drill D may be loosened in the holder 50 andturned to position the other lip of the drill for engagement with theabrading wheel lil.

What I claim is:

1. A drill grinding means comprising a support, a stem adjustablycarried by said support, a plate carried by said stem, a carriagemounted for horizontal adjustment on said plate, a pair of upstandingspaced apart ears carried by said carriage, said ears having axiallyaligned bores therethrough, a rotatable spindle journaled in said ears,means for locking said spindle against rotation, a pair of spaced aparteccentric rigidly secured to said spindle between said ears, a drillclamping cradle, and a pair of spaced apart downwardly extending earscarried by said cradle, said ears having bores therethrough for thejournaling therein of said pair of eccentrics whereby rotation of saideccentrics will eiect a predetermined movement of said cradle.

2. A drill grinding means comprising a support, a' stem carried by saidsupport, means for vertically adjusting said stem, a plate carried bysaid stem, a carriage mounted for horizontal adjustment on said plate, apair of upstanding spaced apart ears carried by said carriage, said earsbeing provided with axially aligned bores therethrough, a rotatablespindle journaled in said ears, means for locking said spindle againstrotation, an eccentric rigidly secured to said spindle, and a drillclamping cradle rockably journaled on said eccentric whereby rotation ofsaid eccentric will eiect a predetermined movement of said cradle.

VALENTINE NICKOLAS HOER'ST.

